Telephone-transmitter.



PATENTED DEC. 6, 1904.

G. W. TALLBYE TELEPHONE TRANSMITTER.

iiomqys APPLIOATION FILED MAY 19. 1903. 10 Menu.

7 nfss$z I I I UNITED STATES Patented December 6, 1904.

PATENT OFFICE.

ILLINOIS, ASSIGNOR OF ONE-HALF OF ATLANTA, ILLINOIS.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 776,960, dated December6, 1904.

Application filed May 19, 1903.

To all] whmn it ntcty concern.-

Be it known that I, GEORGE W. TALLEY, a citizen of the United States,and a resident of Atlanta, in the county of Logan and State of Illinois,have invented aTelephone Transmitter, of which the following is afull,clear, and exact description.

My invention is an improvement in transmitters for telephones; and theprimary object of my invention is to provide a diaphragm of improvedconstruction which is not affected by moisture, heat, or cold, will moreperfectly transmit voices or other sounds to render more distinct andintelligible telephonic communications, will effectually obviate theharsh, rattling, and sharp metallic sounds usually associated with theordinary telephone, and which shall be durable and will not deteriorateby constant use.

A further object of my invention is to so construct the transmitter asto firmly support the diaphragm and cup containing the carbon intheirproper relation, as well as to provide an adjustment of the parts,readily and conveniently accomplished, whereby the volume of soundtransmitted by the apparatus may be regulated.

In the use of telephones, especially those established for publicservice. it is customary to inclose the apparatus in a booth, so thatprivate conversation can be carried on, inasmuch as with the use of theordinary diaphragm it is necessary that the speaker talk distinctly inorder to be heard at the other end of the line. By practical use I havefound that telephones equipped with my improved diaphragm, hereinafterdescribed, will transmit voice and other sounds so clearly anddistinctly that it is possible for a whispered conversation to becarried on, thereby insuring privacy when desired even though theapparatus itself may be located openly in a room where others may bepresent, also that by an adjustment of the transmitter the volume ofsound emitted from the receiver may be so loud as to be distinctly andclearly heard all over a room of ordinary size.

In the use of telephones in submarine work it has been found difficultto produce a trans- Serial No. 157,813. (No model.)

mitter in which the diaphragm will not be affected by moisture andtemperature, and these objections heretofore experienced are obviated bythe construction of diaphragm in accordance with my invention.

In the following specification I have entered into a detail descriptionof my invention, and what I claim as novel, and desire to protect byLetters Patent, is more specifically set forth in the appended claims.

In the accompanying drawings, which form a part of this specification,Figure 1 is a side elevation of a telephone-transmitter constructed inaccordance with my invention. Fig. 2 is a vertical transverse sectionalview. Fig. 3 is a rear view of the support for the diaphragm andcarbon-cup, the said latter being removed. Fig. 4 is a detail view ofthe diaphragm. Fig. 5 is a detail sectional view of the diaphragm,enlarged in thickness to indicate the several layers of which it iscomposed.

Similar letters of reference indicate similar parts in the several viewsof the drawings.

In carrying out my invention the transmitter proper is constructed ofpractically three partsto wit, the support A and the two-part casing BB, the part B of said casing carrying the usual mouthpiece 5. Theseparts are connected by threading the two parts of the casing onto thesupport.

The support A comprises a ring the circumference of which is threaded atits edges in opposite directions, as at (b to receive the parts of thecasing, and at one edge of said ring is an inwardly-projecting annularflange (:4, adapted to receive the diaphragm O, hereinafter particularlydescribed, and within said ring are rearwardly-curvcd radial ribs (0'.integrally connected at the center of the ring or support and formingthe support for the cup D, which contains the carbon, the said centralconnecting portion being apertured, as shown, for this purpose. The cupD, which contains the granulated carbon, is made of carbon, as is usual,and is therefore insulated from the easing by the insulating material s.The diaphragm O is attached by screws 0 to the front face of the annularflange (4- of the ring or support A in proper relation to the cupcontaining the carbon, so that the latter may receive the impulsescaused by the vibrations of said diaphragm.

The diaphragm C consists of several layers, (see Fig. 5,) the firstbeing a sheet of fabric f such as silk, linen, cotton, jute, &e. uponwhich is spread a thin coating of carbon To this is glued or otherwiseattached a sec ond sheet of fabric f, and to the latter is also glued orotherwise attached a thin film of mica, glass, celluloid, or similarmaterial, as a the faces of the diaphragm being protected by a coatingof shellac or varnish. Several layers of the fabric and mica or glassmay be added when desired for certain purposes for which the transmittermay be adapted. Upon the back of the diaphragm, or that opposite themica or glass covering, is a thin and narrow metal cross-piece c,tapering in width from each end to the center, and though shown as asingle strip the same may be composed of two pieces or strips and eitherin contact at the center of the diaphragm or slightly separated.

A diaphragm constructed as hereinbefore described is extremely sensitiveto sound- Waves and will transmit the vibrations to the wire withoutlosing much of the natural tone of voice, volume, force, or pitch.

It will be understood that the metal crosspiece 0 of the diaphragm formsthe front electrode and the granulated carbon in the cup D the rearelectrode. The cup D is slightly removed from the diaphragm, and at itsedge is provided the usual means for preventing the carbon from fallingout.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

l. A diaphragm for telephones comprising a sheet of fabric treated withcarbon, a mica covering, and a protecting-surface 0f shellac or varnish.

2. A diaphragm for telephones, comprising a sheet of fabric coated withcarbon, at mica covering, and a protecting-surface of shellac orvarnish.

3. A diaphragm for telephones, comprising a sheet of fabric coated withcarbon, a mica covering, and a thin and narrow metal strip extendingacross one face of the diaphragm.

4. A diaphragm for telephones, comprising a sheet of fabric coated withcarbon, at second sheet of fabric attached. thereto, and a covering ofmica.

5. A diaphragm for telephones, comprising a sheet of fabric coated withcarbon, a second sheet of fabric attached thereto, a covering of mica,and a protecting-surface of shellac or varnish.

6. A diaphragm for telephones, comprising a sheet of fabric coated withcarbon, a second sheet of fabric attached thereto, a covering of mica,and a protecting-surface of shellac or varnish, together with a thin andnarrow metal strip extending across the face of the diaphragm.

7 The combination,in a telephone-transmitter, of the diaphragm, and athin and narrow strip of metal extending across the face of thediaphragm and tapering in width from each end to the center.

8. A telephone-transmitter, comprising a ring having oppositescrew-threads on its periphery, said ring having an inwardly-projectingannular flange and radial arms the latter connected together at thecenter, together with caps threaded on the periphery of said. ring, onecarrying the mouthpiece, whereby the diaphragm is adapted to be attachedto the annular flange and the cup containing the carbon to the radialarms.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

GEORGE V. TALLEY.

\Vitnesses:

ROBERT D. MoKowN, JAs. E. J EWETT.

